STUDY CITES PERIL IN WORLD AGRICULTURAL DECLINE

By PHILIP SHABECOFF, Special to the New York Times

Published: March 29, 1982

WASHINGTON, March 28—
Deteriorating biological systems around the world pose a grave threat to the global economy, according to a new report issued by the Worldwatch Insitute.

The report warns that excessive pressure on crop and grazing lands, forests and fisheries, combined with continued rapid population growth, portend inevitable declines in living standards in many nations and regions of the world.

It asserts that the decline already has started in the area south of the Sahara in Africa and may soon begin in the Andean region of South America. Even the major industrial nations will not be spared over the long run if these trends continue, it concluded.

''It is increasingly clear that the world is on the edge of an environmental crisis that is undermining the global economy,'' in the view of the institute, a private research organization concerned with international economic and environmental problems. International Effort Sought

The report, issued on Friday and entitled ''Six Steps to a Sustainable Society,'' calls for international efforts to address environmentally based economic problems that, it says, are beginning to afflict many countries without regard to their political or economic systems.

The report was written by Lester R. Brown and Pamela Shaw and is based on Mr. Brown's recently published book, ''Building a Sustainable Society.''

At a news conference held to introduce the report, Mr. Brown commented: ''If we want to know what economic indicators will be like 10 years from now, we should look at the ecological indicators of today. If we want to know, for example, what will be happening to food prices by the end of the century, we should look to soil erosion today.''

In 1964, the report points out, the per capita world production of wood peaked and has been declining since. In the 1970's per capita world production of fish, beef, grain and oil also peaked and declined, all after a long period of uninterrupted growth. Causes of Decline

These trends are unlikely to be reversed without a concerted effort because they are caused by severe environmental degradation and excessive exploitation, the report contends. Wood production is declining because of deforestation, it says. Food production is down because of soil erosion and the spread of deserts. Cattle lands have been overgrazed and oceans and lakes overfished.

Meanwhile, continued rapid population growth is inexorably increasing demand for the products of the earth's biological system, the report says. Projections, such as one by the United Nation, that the world population will stabilize at around 10 billion, compared to today's 4 billion, are based on assumptions of economic development by countries where the growth rate is highest. But the very fact of rapid population growth combined with the deteriorating biological systems will lead to economic decline rather than growth and continued high birth rates, the report argues.

These trends are so new, Mr. Brown said, that policy makers in most governments are not fully aware of them and their implications. The report lists six steps that must be taken if economic decline is to be averted and sustainable growth achieved worldwide:

- Population must be stablized gradually so that it levels off at the 6 billion mark around the year 2020.

- Soil erosion and other soil losses must be reversed.

- A large scale, sustained global reforestation program must be undertaken.

- Energy must be conserved through creation of a more energyefficient economic system.

- Renewable sources of energy must be developed. ''Efforts to put society on a sustainable footing will tax the capacity of individuals and institutions everywhere to change and adapt to the new circumstances,'' the report says. ''Some forwardlooking countries with effective leadership will adjust in time to avoid severe economic and social stresses. Others will learn the hard way.''